The disclosure of Japanese Patent Application No.2000-259850 filed on Aug. 29, 2000 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The invention relates to a vehicular brake control apparatus which includes a braked member rotatable together with a wheel, a braking member disposed so as to have a clearance with respect to the braked member, and an actuator that moves the braking member into contact with the braked member, and that then pressurizes the braking member, and which controls the actuator. The invention also relates to a control method for the vehicular brake control apparatus.
2. Description of the Related Art
The aforementioned type of apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-46082. The disclosed apparatus converts a rotating movement of an electric motor into a linear movement and, due to the linear movement, presses a pad, that is, a braking member, to a disc rotor, that is, a braked member, so as to generate braking force. Furthermore, this apparatus changes the clearance between the pad and the disc rotor in accordance with the state of running of the vehicle so as to improve the responsiveness during an early period of braking and reduce the noises produced when the pad is pressed against the disc rotor.
However, the above-described related art does not change the speed of the pad moving over the clearance. In some cases, therefore, the art may cause the pad to strongly strike the disc rotor, thereby producing a shock on the vehicle in some cases. Furthermore, if the actuator is an electric actuator such as an electric motor or the like, it is conceivable that the noise caused by the driving of the actuator will be great. This problem can be solved by reducing the moving speed of the pad (the driving speed of the electric actuator). However, the reduction of the moving speed of the pad is expected to involve a reduction in the braking responsiveness.
It is an object of the invention to provide a vehicular brake control apparatus that achieves good braking responsiveness of a vehicle and good reduction of the noise produced during braking, and a control method of the apparatus.
One aspect of the invention is a vehicular brake control apparatus including a braking member disposed so as to have a clearance with respect to a braked member that rotates together with a wheel, an actuator that moves the braking member into contact with the braked member and then generates a force for pressing the braking member against the braked member, an actuator control device that controls the force generated by the actuator based on a brake operation performed by an operating person, an operation state detecting device that detects a state of operation of a vehicle, and a moving speed changing device that changes a control performed by the actuator control device so that a speed of the braking member moving toward the braked member is changed in accordance with the state of operation detected by the operation state detecting device.
According to the above-described apparatus, the braking member is moved by the force generated by the actuator until it contacts the braked member. During the movement of the braking member, the moving speed changing means changes the speed of the braking member moving toward the braked member by changing the control performed by the actuator control device to control the force generated by the actuator in accordance with the state of operation of the vehicle, for example, the magnitude of the vehicle speed, the presence/absence of a parking brake operation request, etc. Therefore, during a predetermined state of operation of the vehicle, the speed of the braking member is increased to maintain good initial braking responsiveness. Furthermore, during a difference state of operation, the speed of the braking member is reduced to reduce the noises related to braking operation. Hence, it is possible to provide a vehicular brake control apparatus wherein the braking responsiveness is good and noises that irritate an operating person are not caused by braking.